1. Field of the Invention
The present invention relates to the field of conveyors and in particular relates to accumulating roller conveyors having means for automatically disengaging and engaging the driving force from a momentarily stopped object on the conveyor.
2. Description of the Prior Art
In many applications it is desirable to selectively disengage certain numbers of rollers on a conveyor from the driving force when one or more objects, which are placed on the rollers are momentarily accumulated. At a selected moment, it is also desirable to re-engage the previously disengage rollers to a driving force to once again propel each accumulated or stopped object along the path of the conveyor. In the prior art, mechanisms for selectively engaging and disengaging rollers from a driving force to permit this accumulating operation, have been characterized by complex automatic hydraulic, electric and mechanical means. Typically, the operation of such means involves great expense, consumes a substantial amount of energy, may require additional control mechanisms beyond the basic propulsion means of the conveyor system, and tends to produce high noise levels. What is needed then, is an accumulating roller conveyor which is reliable, inexpensive, simply constructed and yet may selectively disengage and engage any number of rollers from a driving force according to the momentary passage or stoppage of objects upon the conveyor.